I was messing around with the injector advance tables in the aem ems and would like to hear some discussion on this. I was thinking about setting up the tables to inject just after the intake valve opens as long as im at low load/rpm. At higher loads where the pulsewidths are longer i will calculate how much in advance i will need to start injecting so that the injection will finish before the valve closes. Is this a good way to approach it? The numbers in there now indicate injecting way before the valve opens. Now i know spraying on the closed valve promotes fuel atomization but it just seems more logical to spray when the valve opens.

any thought on this?

cliff notes: inject before intake valve opens, or just after?

 

you can get pretty close by just changing the injector sync.. what i do is lower the partial load section of the injector advance map b/c the pulse width will be very short in those areas. also rember that the closer to 100% duty cycle you get the less this map matters. you can make idle and part throttle alot nicer with this map, especially if you have large injectors.

 

Yea, thats why i started messing with it because my idle was perfect then i dropped in some larger injectors (50lb) and they wouldn't idle any leaner than like 14:1. Now in the basemap injector 1 is set to trigger at the 12th tooth on the crank which is at the top of the intake stroke but the injector phase was set to 17 for some reason. Add 17 to 12 = 29 - 24teeth = about 5 teeth. 5 * 30deg per tooth is 150 degrees after TDC on compression stroke. That really doesn't make sense.

The intake valve on a b16 opens at 10 deg btdc and closes 40 deg abdc which means it is open for 180+10+40 = 230 degrees of crank rotation. To be safe ill assume 200 degrees and run 0 or very little advance for all pulsewidths that can complete in less than 200 degrees of crank rotation. Ill advance the rest accordingly and should end up with an optimal 3d injector advance map. As you stated it will probably only really make a difference at idle but well see.